Fig. 6. Brk is a potential D-h repressor. (A) D-h-GFP expression (green) relative to brk-lacZ expression (red) in a wild-type leg disc. (B,C) brk-lacZ expression in a wild-type leg disc (B) and a dpp hypomorph (dppd6/dppd12) leg disc (C). (D,G) Overexpression of brk, in UAS-brk/+; dpp-Gal4/+ legs, results in drastic reduction of D-h-GFP expression (D) and D-h-C-GFP (G), while HHRE-GFP (E) and D-h-CB-GFP are still expressed (F). It appears that in legs overexpressing brk, there are fewer HHRE-GFP and D-h-CB-GFP-expressing cells. This is probably due to compromised growth of leg discs when Brk levels are elevated near the AP boundary (Jazwinska et al., 1999).